Friction draft and buffing mechanism.



I. SIMPSON. FRIGTION DRMTT AND BUFPING MBGHANISM.

APPLICATION FILED AUG. 19, 190B.

Patented Aug. 27, 1912.

2 SHEETS-SHEET 1.

NN WN mv JNVENTUR Isaac Sim/501g WLTNESSES man.

l V1. SIMPSON. l FBIGTION DRAFT AND BUFPING MBGHANISM.

APPLICATION FILED AUG. 19, 190B.

1,036,920. Patented Aug. 27, 1912;

2 SHEETS-SHEET 2.

WITNESSES n IENTR Isaac Sim/275022,

ATTRNEY ISAAC SIMPSON, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR, BY DIRECT AND MEsNE ASSIGNMENTS, To THE WESTINGI-IOUSE AIR BRAKE COMPANY, 0F PITTS- BURGH, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA FRICTION DRAFT AND BUFF-ING MECHANISM.

l Specification of Letters Patent.

Patented Aug. 27, 1912.

Application filed August 19, 1908. Serial No. 449,284.

This invention relates to friction draft and buiiing mechanism, and particularly tov cars.

friction draft gears for railway provide The object ofthe invention is to mechanism of the character specified, which is of very simple construction, which is durable, which develops a large capacity under bufiing and draft strains, and which releases i with certainty and ease after compression.

With the' above objects in view, the invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the accompanying drawings, Figure 1j is a horizontal sectional view of the improved mfriction mechanism, showing a por` tion of the draft sills of a railway car and a portion of the' drawbar; Fig. 2 is a'transverse section on the line .ac-w,

nism, the'front follower late being omitted; Fig. 4 is a longitudinai) section showing a slight modiiication of the friction mechanism; Fig. 5 is a front end view of th'e housing; and Figs. 6- and 7 are perspective views respectively of the wedge block and the inner friction member o'r blocks.

vIn the drawings, the center or draft sills of the car are shown at 1.

2 designates the usual draw-bar, to one end of which is secured the usual yoke or strap 3.

4 4and 5 designate respectively the front and rear follower plates, mounted within said yoke and adapted tobear against the ltwo pairs of draft lugs 6 and 7, all as is side edges are flanged as at 14, to stiHen the Fig. 1; Fig. 3 is a front end view of the friction mecha- Said wedge blocks 25, against which the end bears.

same. Within the housing are the posterior springs 9 and 10, one of which surrounds the other, and one of which is preferably considerably larger than the other, as shown. These springs at their forward ends, bear against a division plate or partition 11, and at their opposite ends bear against the transverse plate 15. The rear ends of these springs, are held in proper position or 'centered bymeans of a boss 17, punched out of the plate 15, and entering the end of the spring' 10. The forward ends of these springs are held in proper position by means of semi-cylindrical flanges 18, on the inner `friction blocks or members 16. The artition plate 11, is seated against inward y projecting flanges 19, on the friction blocks 16, and the iianges 1,8, project rearwardly sufficiently yfar to inclose the ends of the springs 9 and 10.

. -In the forward end of the housing are lolcated the two outside or stationary friction members or blocks 20, which as s own in Fig. 2, fit snugly against the side walls 'of the housing and are held against longitudinal movement in the housing by means of lugs 21, on said blocks entering holes in the housing, The inner faces of these friction blocks are slightly tapered, as shown in Fig. 1. The inside friction blocks or members 16, have their outer faces correspondingly tapered and coperate with4 the outer friction members to produce the necessary friction in the' operation of the gear. lIn order to create the necessary friction between the blocks' 16 and 20, suitable means are provided 'for spreading` the blocks 16, or forcing the same outwardly against blocks 20. The spreading `means illustrated comprises a pairof i with inclined faces 22 cooperating with "similar inclined faces 23 on the inner friction members 16.v The ,have their inner faces wedge blocks 1 3, formed substantially as at 24, Fig. `6 and inthe anterior spring 12. at their rear ends .are provided with inwardly projecting fianges of the spring 12, l The spring 12, ma be either slightly shorter than the wedge b ocks 13, as shown in Fig. 1, so that it is not acted on by the semi-cylindrically, closel or surround wedge blocks 13, provided of t-he coils of said springs, due to the fact that the pressure of said spring against the flanges 25,- tends to force the wedge blocks 13, rearwardly and the lbeveled faces on the vwedge blocks and inner friction blocks force the wedge blocks toward the axis of the gear and against the outside of the coils of the sprin l 12. This friction on the outside of the coils gives a. suitable capacity in -the preliminary action of the gear with a sli htrecoil. In this modification the front ollower plate may contact first with either the wedge blocks 13, 'or inner friction blocks 16', while in Fig. 1 the wedge blocks 13, are always in contact with the followerpplate during the'inner travel of the gear, although the friction blocks 16, may also contactwith the follower plate; This is gov-v v erne'd lby the strength of the spring 12.

.at any time.' l

The inner faces of thex inner friction Preferably this vspring is made strong enough, and the'distance `between the folf lower plate-andtheends of the friction blocks 16, is such, that said follower late does notl contact with Vsaid'xfrictionbrooks blocks 16, are recessed and ribbed asy shown in Fig. 7, in order to give the necessary strength with minimum weight. These friction blocks are provided with the side fianges 26, between which the wedge blocks are seated. It is the-usual practice, when the friction blocks and the co-acting friction plates are of different relative degrees of hardness, to make the friction plates, correspondingr to the plates 20, of a comparatively soft metal, such as malleable iron, and the inner friction blocks, corresponding to the blocks 16. of a harder metal, such as chilled cast iron or steel. The latter metal is, of course, more brittle than the former, and frequently the harder blocks break. In my friction mechanism, the inner friction blocks or members 16. are made of the softer metal, and the outer friction plates or members 20, of thc harder or more brittle metal. The latter fit closely against the side Walls of the housing', and are backed and reinforced over their entire outer surfaces so that breakage is practically impossible, even though thc outer plates be made of very brittle metal.

The housing 8, shown in the drawings is formed ot' metal, suoli as from a section of wrought iron or steel tubing'. The walls are shown of uniform thickness from end to end and the transverse plate 15, is suitably secured 'to said walls as'by welding the same thereto. The wrought metal housing gives maximum strength with minimum weight, and .is much more reliable than the cast housings ingeneral use.

In operation, the stresses tending ,to shorten the gear tend to,.force the Wedge blocks 13, towardthe rear, but by reason of the inclined faces 22 and 23, on said wedge v blocks and inner friction blocks respectively, the latter are also forced toward the rear,

sliding oni'the inclined 'or tapered` faces of the outer friction blocks. The rearward travel of the inner friction blocks along such inclined faces causes the inner friction blocks move apart longitudinally, which, of course,

would cause an outward' movementl from each other on their bevels. But as thepressure at the bevels'v'of saidjblocks is trans-v mitted toward the axis of the ,friction mechv anism, said pressure is-vresisted radially o'r centrifugally by thel anteriorfspring 412, which radial' actionnpro'vides space ltoga'ccommodate the parts, thereby'compensating,

or *mayv vbe made `to more `than compensate, j according to the strength of anterior spring- 12, the morelcircumsciibed area within the outer friction plates 'into which the friction mechanism is being compressed. This completely eliminates ,the outward movementfromeach other ofthe wedge blocks 13', and Vthe friction blocks 16, andallowsthe spring 12,.to be compressed without any'l movement outwardly upon each other of the'bevels 'of friction blocks'v 16, and wedge blocks 13. The strength and resistance of'this 'spring 12,Y determinesthe amount of pressure exist y ing between the friction blocks or members.

The posterior springs," of. course,rare com- A pressed under the inward 'and rearward movement of the inner friction blocks., Asv

soon as the friction Amechanism is relieved from the pressure which shortens the same,

the first action is for the s rin 12, to 'exi pand radially or centrifuga ly,`t us tending' to force the wedge blocks 13, radially' or outl' f wardly, and by reason of the wedge faces between said blocks andthe inner friction blocks, this force is expended in causing the wedge blocks to move forwardly or in a direction to lengthen the friction mechanism. Consequently the pressure of the inner friction blocks is instantly and certainly released, so that the posterior springs 9, and 10, need merely push the inner friction blocks forwardly, and this action occurs gradually and easily. The bevels or wedge facesv on the blocks 13 land, 16 canibe made steep enough to give a Very high capacity without any danger of sticking.

The friction mechanism described is composed of a minimum number of parts, all of simple and. strong construction. The mechanism is, therefore, cheap to manufacture, is very durable and strong, develops a high capaclty of friction in the closing movement thereof and releases easily and with cern taint W at I claim is: f,

l. In friction draft and 4buiting mechanism, the combination with a casing, of -cooperating inner and outer friction members contained in said casing, a longitudinally arranged posterior spring acting against the inner friction members, spreading means acting on theA inner friction members, and a longitudinally confined coiled spring inclosed by said spreading means and acting radially on said spreading means.

2. In friction draft and bufing mechanism, the combination with a casing, of co- -operating inner and outer friction members mounted in said casing, a` longitudinally arranged posterior spring acting against the inner frlction members, wed e blocks arranged to spread said inner riction members, and a lon i'tudinally confined coiled spring inclosed y said Wedge blocks and acting radially on said Wedge blocks.

3. yIn friction draft and buiiing mcchanism, the combination with a casing, of cooperating inner and4 outer friction members mounted in said casing, a longitudinally arranged posterior spring acting against the inner friction members, wed e blocks ar ranged to spread said inner iction members and provided at their posterior ends with inturned flanges, and a coiled spring inclosed by said wedge blocks and bearing against the end ianges thereof.

4f. In friction draft and Abuiiing mechanism, the combination with a casing, of cooperating inner and outer friction members mounted therein, a longitudinally arranged posterior spring seated against the ends of said inner friction members, Wedge blocks acting directly against said inner friction `members and acting to spread the same, and

a spring inclosed by and adapted to act radially on said wedge blocks.

5. In'friction draft and butling mechanism, the combination with a casing, of cooperatingl inner and outerfriction members mounted therein, flanges on the posterior ends of said inner friction members,.a longi tudinally arranged Vposterior spring acting on and having its end ositioned by the flanges of sald inner riction members, spreading means acting on said innerl frictlon members, and a coiled s ring inclosed by said spreading means an acting radially to control the action thereof.

6. In a friction draft and bufling mechanism, the combination with a vcasing having longitudinal friction faces and friction members having friction surfaces adapted to engage the'frictio'n faces of the casing, of

Wedge blocks for spreading the friction ,l

members against the casing. and a spring confined axially and loiitudinally by said wedge blocks and adap said wedge blocks. l

-In testimony whereof, I have hereunto set my hand. V

" SAC SIMPSCVL*` Witnesses: 4

l H. C. LOUDENBECK, y Jamas G. S'roNnB.

to act radially on 

